EAGER: Collaborative Research: A Novel Method for Laminar Burning Speed Measurement at Ultra High-Pressures

下一代先进燃烧装置将在超高压条件下运行，以提高燃烧效率，减少污染物排放。然而，在这种极端条件下，火焰往往变得不稳定，基本性质的实验测量变得具有挑战性。该项目的主要目的是提供一个详细的时间和空间分辨测量的点火过程中的高压。此外，测量方法和开发的计算模型将通过实现设计和优化在极端条件下运行的先进燃烧设备的预测能力，对燃烧和等离子体社区产生广泛而有价值的影响。该项目还将包括重要的教育活动，包括课堂和社区参与，将研究融入相关课程，本科生研究计划和K-12学生的推广计划。该项目的主要目标是开发一种新的方法来测量超高压下球形膨胀火焰在点火影响区域的LBS。该区域的复杂性在于，核生长速率不仅取决于化学反应，而且还取决于其他项，例如能量释放以及辐射和传导能量损失。由于电离气体的产生（即，等离子体）。本研究将通过实验和模拟相结合的研究来填补这一空白，主要有三个目标：（1）使用一个定义明确、控制良好的高压实验装置;（2）发展一个自洽的理论框架来解释能量放电对等离子体形成和初始火焰传播的影响;以及（3）修改可用的高保真直接数值模拟（DNS）代码以说明等离子体核和点火过程的演变。在实验方面，该项目将利用等离子体核传播的高速成像以及先进的激光诊断。等离子体的性质将使用统计热力学计算。该项目旨在首次从根本上了解控制超高压点火的高时空分辨率的物理化学过程。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The next generation of advanced combustion devices will operate under ultra-high pressure conditions in order to improve the combustion efficiency and reduce emission of pollutants. However, at such extreme conditions, flame tends to become unstable and experimental measurement of fundamental properties becomes challenging. The principal aim of this project is to provide a detailed time- and space-resolved measurements of the ignition process at high pressures. In addition, the measurement methodologies and developed computational models will have a broad and valuable impact on combustion and plasma communities by enabling predictive capabilities for designing and optimizing advanced combustion devices operating under extreme conditions. The project will also encompass significant educational activities, including classroom and community engagement, integration of research into relevant courses, undergraduate research program, and an outreach program for K-12 students.The main goal of this project is to develop a novel method to measure LBS in the ignition affected region using a spherically expanding flame under ultra-high pressures. The complication with this region is that, the kernel growth rate does not only depend on the chemical reaction but also on other terms such as energy discharge, as well as radiative and conductive energy losses. None of these terms has been adequately assessed, due to the generation of ionized gas (i.e., plasma). The proposed research will fill this broad knowledge gap via combined experimental and modeling studies focused in three specific aims: (1) using a well-defined and well-controlled high-pressure experimental configuration; (2) developing a self-consistent theoretical framework to explain the influence of energy discharge on the plasma formation and initial flame propagation; and (3) modifying an available high-fidelity direct numerical simulation (DNS) code to account for the evolution of the plasma kernel and the ignition process. On the experimental side, the project will utilize high-speed imaging of the plasma kernel propagation in conjunction with advanced laser diagnostics. The plasma properties will be calculated using statistical thermodynamics. This project, for the first time, aims to fundamentally understand the underlying physicochemical processes controlling the ultra-high pressure ignition in a high temporal and spatial resolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.